<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		*{
			margin: 0;
			padding: 0;
		}
		.container{
			width: 800px;
			height: 800px;
			border: 1px solid red;
			display: flex;;
			flex-direction: column;
			/*align-items: flex-end;*/
			justify-content: flex-end;
		}
		.box{
			width: 100px;
			height: 100px;
		}
		.a{
			background-color: blue;
		}
		.b{
			background-color: green;
		}
		.c{
			background-color: pink;
		}
	</style>
</head>
<body>
	<div class="container">
		<div class="box a"></div>
		<div class="box b"></div>
		<div class="box c"></div>
	</div>
</body>
</html>